Sealing assembly for bearings, in particular for use in agriculture

ABSTRACT

A sealing assembly for bearings, in particular for use in agriculture, comprising a primary sealing barrier and a secondary sealing barrier, which are arranged in series along a potential path (P) of ingress of contaminants into the bearing, and have, respectively, a first seal and a second seal with a plurality of contact lips. The contact lips of the first and second seal with a plurality of contact lips may be static lips that do not rotate about an axis (A) of rotation of the bearing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority to Italian PatentApplication No. 102021000014132 filed on May 31, 2021, under 35 U.S.C. §119, the disclosure of which is incorporated by reference herein.

FIELD

The present disclosure relates to a sealing assembly for bearings, inparticular for use in agriculture.

BACKGROUND

CN205013509U describes a sealing assembly for bearings which, althoughnot explicitly intended for use in agriculture, is nonetheless able towithstand challenging environments, exactly like those encountered whenworking the land in agriculture, and which comprises a primary sealingbarrier and a secondary sealing barrier.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will now be described with reference to the attacheddrawing, which illustrates non-limiting exemplary embodiments of thedisclosure, in which:

FIG. 1 is an axial cross-sectional view of a sealing assembly forbearings, in particular for use in agriculture, according to exemplaryembodiments of the present disclosure, and

FIG. 2 is an enlarged view of the sealing assembly of the bearing ofFIG. 1 .

DETAILED DESCRIPTION

A primary sealing barrier is supported by the inner ring of the bearingand comprises a first laminar shield which extends from an outer surfaceof the inner ring to an inner surface of the outer ring; and a secondarysealing barrier is supported by the outer ring and comprises a secondlaminar shield which extends from an inner surface of the outer ring tothe outer surface of the inner ring: the first and the second shieldshave respective cylindrical mounting bodies fitted on the outer surfaceof the inner ring and on the inner surface of the outer ring,respectively, and respective cylindrical support bodies, which areconnected to the relative cylindrical mounting bodies by respectiveannular flanged bodies: each cylindrical support body of each shield isradially inserted between the cylindrical mounting body and thecylindrical support body of the other shield.

The primary sealing barrier further comprises a first seal with aplurality of lips, which is supported by the relative cylindricalsupport body, and is provided with three lips in contact with a frictionsurface of the cylindrical mounting body of the secondary sealingbarrier; and, likewise, the secondary sealing barrier also furthercomprises a second seal with a plurality of lips, which is supported bythe relative cylindrical support body, and is provided with three lipsin contact with a friction surface of the cylindrical mounting body ofthe primary sealing barrier.

Since the sealing device is mounted inside the bearing between the innerring and the outer ring, there is a potential path for the ingress ofcontaminants into the bearing, and the three sealing lips of the primarysealing barrier are arranged along this path upstream of the threesealing lips of the secondary sealing barrier, making this path somewhattwisted and difficult for any contaminants to pass through completely.

In the sealing assembly described above, the sealing lips of the twosealing barriers have respective constant radial lengths and, duringassembly of the sealing assembly, as they come into contact with therelated friction surfaces, they bend substantially in the same way,creating ostensibly optimal conditions of contact in terms of pressureand sealing. However, in use, because of both the stresses to which therelative bearings are subjected and the type of contaminants to whichthey are exposed, they may wear out very quickly, the sealing assemblyitself thus losing its sealing capacity.

Moreover, again in the sealing assembly described above, while theprimary sealing barrier is connected to the inner ring, which is a fixedring of the bearing, the secondary sealing barrier is connected to theouter ring which, conversely, is a rotating ring of the bearing, andtherefore while the three contact lips of the first seal with aplurality of lips are static non-rotating lips, the three contact lipsof the second seal with a plurality of lips are, conversely, dynamicrotating lips and it is necessary to make different structuralarrangements for the first and second seal with a plurality of lipssince one of the two is subjected to centrifugal forces which, in use,result in substantial variability of sealing conditions.

The present disclosure relates to a sealing assembly for bearings, inparticular for use in agriculture, that can overcome one or more of thedisadvantages found in the prior art. In particular, one major aim ofthe disclosure is to improve the efficiency of the seal withoutincreasing friction, for any type of bearing system that requires a highdegree of reliability, including under extremely contaminatingconditions and, moreover, where there is some potential for misalignmentbetween the rings of the bearing.

Referring to FIG. 1 , the reference sign 1 generally designatesexemplary embodiments of a sealing assembly for a bearing unit 10, inparticular for a bearing unit for use in agriculture.

The bearing unit 10 may include a flanged outer ring 11; a radial flange12 rigidly secured to the flanged outer ring 11 for mounting a disc D bymeans of bolts (not shown) mounted in a series of axial holes 13; tworaceways 14 a, 14 b formed on the inside of the flanged outer ring 11for housing respective rows of rolling bodies 15 a, 15 b; and for eachraceway 14 a, 14 b, a respective inner ring 16 a, 16 b axially adjacentto the other inner ring 16 b, 16 a and both mounted on a central supportshaft A. The flanged outer ring 11 may be stationary and the inner ring16 a, 16 b may be rotatable with central support shaft A, for example.

The rings 16 a, 16 b may be provided with respective raceways, tworaceways 17 a, 17 b, for housing the rows of rolling bodies 15 a, 15 b.

On the side facing the disc D, the bearing unit 10 may include an O-ringseal 18 housed in a circular groove 19 and pressed between the outerring 11 and the disc D so as to ensure sealing against contaminants thatcould get into internal parts of the bearing unit 10, and a cover 20,radially inside the circular groove 19 for closing off the outer ring 11on the same side as the disc D.

On the side opposite that facing the disc D, the bearing unit 10 mayinclude two cylindrical seats 21 and 22, which are also formed in theflanged outer ring 11, and are arranged in series with one another. Theseat 22 is radially delimited on the outside by an internal cylindricalsurface 23 of the outer ring 11 and is radially delimited on the inside,in the exemplary embodiment shown, by an outer cylindrical surface 24 ofan intermediate support ring 25 arranged axially adjacent to the innerring 16 b and substantially forming part of the inner ring 16 b.

According to various embodiments of the present disclosure, the sealingassembly 1 may include a cassette seal 2 inserted in the cylindricalseat 21, i.e. in the seat 21 closest to the inside of the bearing unit10, and a sealing device 3, which is arranged in the cylindrical seat22, i.e. in the axially outermost seat 22 of the bearing unit 10, andhas the function of preventing the ingress of contaminants resultingfrom the agricultural labor of working the land, certainly into thebearing unit 10 but above all into the cassette seal 2, which willtherefore have a longer service life, enhancing the service life of thebearing unit 10. According to various embodiments of the presentdisclosure, the sealing device 3 is mounted at the intermediate supportring 25, which, as described above, is arranged axially adjacent to theinner ring 16 b and substantially forms part of the inner ring 16 b:alternatively, and with no substantial change to the subject matter forwhich protection is sought, the sealing device 3 may be mounted directlyat the inner ring 16 b, the surface 24 of which may be axially elongatedso as to delimit radially on the inside both the seats 21 and 22. Theexplanation below will refer explicitly to the mounting of the sealingdevice 3 at the intermediate support ring 25 but, as just pointed out,it may encompass, without any limitation whatsoever, the mounting of thesealing device 3 at the inner ring 16 b.

As shown more clearly in FIG. 2 , the sealing device 3 may include aprimary sealing barrier 4 and a secondary sealing barrier 5, which arearranged in series along a potential path P of ingress of contaminantsinto the bearing unit 10, and may include a first seal 41 with aplurality of contact lips and, respectively, a second seal 51 with aplurality of contact lips. The contact lips 42 and 52 of the first andsecond seal 41 and 51 are static contact lips 42 and 52 that do notrotate about the central axis A, i.e. about the axis of rotation of thebearing unit 10.

Both the first seal 41 and the second seal 51 have the same number ofcontact lips 42 and 52: in particular, in the embodiment of the presentdisclosure shown in FIGS. 1 and 2 , there are three contact lips 42 and52, but depending on the use to which the bearing unit 10 is put, twocontact lips may be sufficient for less demanding uses, or more thanthree, and up to five or six contact lips may be required for moredemanding uses, possibly when working on land with a greater degree ofcontaminants.

In any case, the explanation below refers to the case in which there arethree contact lips 42 and 52 in which, moreover, the contact lips 42 and52 of the first and second seal 41 and 51 may have radial dimensionsdecreasing along the ingress path and are inclined, when in a freeconfiguration prior to assembly, with respect to the axis of rotation ofthe bearing unit 10 with the same inclination and so as to be convergenttowards the inside of the bearing unit 10.

The contact lips 42 of the first seal 41 with a plurality of contactlips and the contact lips 52 of the second seal 42 with a plurality ofcontact lips may be made of polymer material, start from respectivebases 43 and 53 made of the same material, and the gradual reduction inradial height of the contact lips 42 and 52 is obtained by means of agradual axial increase in a radial thickness of the relative base 43 and53. The possibility of having contact lips 42 and 52 of different radialheights, in which the contact lips 42 and 52 of greater radial heightare those further upstream along the path P, first of all makes itpossible to better control the final position, in use, of said contactlips 42 and 52, which will not touch one another, thus making itpossible to expel contaminants more effectively. In particular, thecontact lips 42 and 52 of greater radial height will also be moreflexible than the contact lips 42 and 52 of lesser radial height,allowing both the first seal 41 and the second seal 51 to adapt easilyto possible misalignments of the components of the bearing unit 10 or ofthe sealing assembly 1 resulting from particularly harsh and difficultconditions of use of the bearing unit 10, while the lesser flexibility,or increased rigidity, of the contact lips 42 and 52 of lesser radialheight will give the latter greater frictional contact force, ensuringfurther and better sealing against the ingress of any contaminants alongthe ingress path P.

At the same time, having contact lips 42 and 52 all with the sameinclination, in their free configuration prior to assembly, makesinversion of the contact lips 42 and 52 especially difficult, if notentirely unlikely, both during assembly of the sealing assembly 1, andwhen the bearing unit 10, and, therefore, the sealing assembly 1 areused in conditions in which the thrust of contaminants along the path Pis particularly strong, for example when ploughing agricultural landand/or during pressure washing of the equipment. Having contact lips 42and 52 all with the same inclination, in their free configuration priorto assembly, also considerably simplifies production, with theconsequent advantages in terms of cost and quality, since the contactlips 42 and 52 can not only be removed from the production mold veryeasily, but without compromising their integrity even slightly.

As will be explained in more detail below, another feature of thesealing assembly 1 of the present disclosure is that the contact lips 42and 52 are static lips, in other words they do not rotate about thecentral axis A, and therefore they are not subject to centrifugal forceswhich, in use, would give rise to substantial changes in sealingconditions. Moreover, because the contact lips 42 of the first seal 41and the contact lips 52 of the second seal 42 are both static, theirstructural and design specifications will be substantially similar,affording further savings not only in terms of final cost price but alsoas regards production times, especially when it is necessary to changethe proportions of the product to adapt it to bearing units 10 ofdifferent dimensions.

According to various embodiments of the present disclosure, the primarysealing barrier 4 is supported by the intermediate support ring 25, i.e.by the inner ring 16 b of the bearing unit 10, and may include a firstshield 44, which extends from the outer surface 24 to the inner surface23 of the outer ring 11, and in turn may include a first cylindricalmounting body 45 fitted on the outer surface 24 of the intermediatesupport ring 25, i.e. of the inner ring 16 b, and a first cylindricalsupport body 46 connected to the relative first cylindrical mountingbody 45 by means of a respective annular flanged body 47. The first seal41 may also include, in addition to the contact lips 41 and the relatedbase 43, a cylindrical covering 48 made of polymer material, directlyconnected to the first cylindrical mounting body 45 and inserted betweenthe first cylindrical mounting body 45 and the outer surface 24 so as toenhance both the sealing of the sealing device 3 and the grip of thefirst shield 44, i.e. of the first cylindrical mounting body 45, on theouter surface 24 of the intermediate support ring 25. Moreover, the base43 may be directly connected to the first cylindrical support body 46,which therefore supports the contact lips 41.

The secondary sealing barrier 5 may, on the other hand, be connected tothe outer ring 11 of the bearing unit 10, i.e. it is not entirelyrigidly secured to the outer ring 11 from the angular point of view, andmay include a second shield 54, which extends from the inner surface 23of the outer ring 11 to the outer surface 24 of the intermediate supportring 25, i.e. of the inner ring 16 b, and in turn may include a secondcylindrical mounting body 55 fitted on the inner surface 23 of the outerring 11, and a cylindrical friction body 56 connected to the relativesecond cylindrical mounting body 55 by means of a respective annularflanged body 57, which has a radial length such that it supports thecylindrical friction body 56 in substantial proximity to the cylindricalsupport body 46 of the primary sealing barrier 4. In particular, thecylindrical friction body 56 may be arranged coaxially to the axis A andto the cylindrical support body 46 and at a radial distance from thecylindrical support body 46 so as to form, with the cylindrical supportbody 46, a cylindrical passage, or, better still, a labyrinth seal 70extending along the ingress path P. Since the cylindrical support body46 may have an end bent portion 46 a, which is inserted radially in thebase 43 so as to support said base 43, the first seal 41 with aplurality of contact lips may include a projecting end portion 43 a,which may project axially from the base 43 beyond the bent portion 46 asubstantially adjacent to the flanged body 57, and has an annularprofile 49, of semi-circular section, which may extend from theprojecting end portion 43 a and may be in frictional contact with theflanged body 57 both to determine a reciprocal axial position ofmounting of the primary sealing barrier 4 and secondary sealing barrier5, and to create a further seal along the path P.

The annular profile 49 and the projecting end portion 43 a are made ofthe same material as the contact lips 42, and the projecting end portion43 a is arranged radially and directly facing the cylindrical supportbody 46 helping to define part of the labyrinth seal 70.

As stated above, the secondary sealing barrier 5 is not entirely rigidlysecured to the outer ring 11 from the angular point of view, and in factthe second shield 54 comprises a further second cylindrical mountingbody 55 a and a second cylindrical support body 58, which are connectedto one another by means of a further annular flanged body 59, but areentirely independent of the second cylindrical mounting body 55 and ofthe cylindrical friction body 56. In particular, the further secondcylindrical mounting body 55 a is mounted on the first cylindricalmounting body 45 of the primary sealing barrier 4, and the contact lips52 of the second seal 51 with a plurality of contact lips are supportedby the second cylindrical support body 58, by insertion in the base 53,in frictional contact with the cylindrical friction body 56 on the sideopposite the cylindrical friction body 56 with respect to the labyrinthseal 70.

Because the secondary sealing barrier 5 may not be entirely rigidlysecured to the outer ring 11 from the angular point of view, or thesecond shield 54 may be split into two independent cylindrical mountingbodies 55 and 55 a, makes it possible to both simplify production andsimplify mounting of the contact lips 52 of the second seal 51 with aplurality of contact lips. To be specific, the second seal 51 may berigidly secured to the assembly made up of the further secondcylindrical mounting body 55 a, second cylindrical support body 58, andfurther flanged body 59, and these elements may be both producedindependently from the rest of the sealing assembly 1 and, therefore,mounted on the first cylindrical mounting body 45 thereby rigidlysecuring to one another, from the static as well as functional point ofview, the contact lips 52 of the second seal 51 and the contact lips 42of the first seal 41. Lastly, once the abovementioned elements have beenmounted on the first cylindrical mounting body 45, the latter may bebent radially outwards at a free end thereof to create an end bentportion 45 a, which may be arranged axially facing the further annularflanged body 59, preventing it from becoming detached accidentally.

In addition to the various embodiments of the disclosure as describedabove, note that it encompasses many other variants. Moreover, note alsothat these embodiments are merely examples and do not limit the scope ofthe disclosure, or its uses, or its possible configurations. On thecontrary, while the above description will allow a person skilled in theart to implement the present disclosure at least according to oneexemplary embodiment thereof, note that many variants of the componentsdescribed are possible without departing from the scope of thedisclosure, as defined in the attached claims, which are interpretedliterally and/or according to their legal equivalents.

We claim:
 1. A sealing assembly for a bearing unit comprising an outerring and an inner ring; the sealing assembly comprising: a primarysealing barrier; and a secondary sealing barrier, wherein, the primarysealing barrier and the secondary sealing barrier are arranged in seriesalong a potential path (P) of ingress of contaminants into the bearing,the primary sealing barrier and the secondary sealing barrier comprise,respectively, a first seal and a second seal each with a plurality ofcontact lips, the contact lips of the first seal and the second seal arestatic lips that do not rotate about an axis (A) of rotation of thebearing unit; the primary sealing barrier comprises a first shield, theprimary sealing barrier is configured to be supported by the inner ringof the bearing unit, the first shield is configured to extend from anouter surface of the inner ring to an inner surface of the outer ring,the first shield comprises a first cylindrical mounting body configuredto be fitted on the outer surface of the inner ring, and a firstcylindrical support body connected to the first cylindrical mountingbody, and the contact lips of the first seal are supported by the firstcylindrical support body.
 2. The sealing assembly of claim 1, whereinthe contact lips of the first seal and the second seal have radialdimensions decreasing along the ingress path (P).
 3. The sealingassembly of claim 2, wherein the contact lips of the first seal and thesecond seal are substantially inclined with respect to the axis (A) ofrotation of the bearing unit.
 4. The sealing assembly of claim 3,wherein the contact lips of the first seal and the second seal havesubstantially the same inclination with respect to the axis (A) ofrotation of the bearing.
 5. The sealing assembly of claim 2, wherein,the secondary sealing barrier comprises a second shield, the secondarysealing barrier is connected to the outer ring of the bearing unit, thesecond shield is configured to extend from the inner surface of theouter ring to the outer surface of the inner ring, the second shieldcomprises a second cylindrical mounting body configured to be fitted onthe inner surface of the outer ring, and a cylindrical friction bodyconnected to the second cylindrical mounting body by an annular flangedbody, and the contact lips of the second seal being in frictionalcontact with the cylindrical friction body.
 6. The sealing assembly ofclaim 3, wherein, the secondary sealing barrier comprises a secondshield, the secondary sealing barrier is connected to the outer ring ofthe bearing unit, the second shield is configured to extend from theinner surface of the outer ring to the outer surface of the inner ring,the second shield comprises a second cylindrical mounting bodyconfigured to be fitted on the inner surface of the outer ring, and acylindrical friction body connected to the second cylindrical mountingbody by an annular flanged body, and the contact lips of the second sealbeing in frictional contact with the cylindrical friction body.
 7. Thesealing assembly of claim 4, wherein, the secondary sealing barriercomprises a second shield, the secondary sealing barrier is connected tothe outer ring of the bearing unit, the second shield is configured toextend from the inner surface of the outer ring to the outer surface ofthe inner ring, the second shield comprises a second cylindricalmounting body configured to be fitted on the inner surface of the outerring, and a cylindrical friction body connected to the secondcylindrical mounting body by an annular flanged body, and the contactlips of the second seal being in frictional contact with the cylindricalfriction body.
 8. The sealing assembly of claim 5, wherein, the secondshield of the secondary sealing barrier comprises a further secondcylindrical mounting body and a second cylindrical support body whichare connected to one another and independent of the second cylindricalmounting body and of the cylindrical friction body, the further secondcylindrical mounting body is mounted on the first cylindrical mountingbody of the primary sealing barrier, and the contact lips of the secondseal being supported by the second cylindrical support body infrictional contact with the cylindrical friction body.
 9. The sealingassembly of claim 6, wherein, the second shield of the secondary sealingbarrier comprises a further second cylindrical mounting body and asecond cylindrical support body which are connected to one another andindependent of the second cylindrical mounting body and of thecylindrical friction body, the further second cylindrical mounting bodybeing mounted on the first cylindrical mounting body of the primarysealing barrier, and the contact lips of the second seal being supportedby the second cylindrical support body in frictional contact with thecylindrical friction body.
 10. The sealing assembly of claim 7, wherein,the second shield of the secondary sealing barrier comprises a furthersecond cylindrical mounting body and a second cylindrical support bodywhich are connected to one another and independent of the secondcylindrical mounting body and of the cylindrical friction body, thefurther second cylindrical mounting body being mounted on the firstcylindrical mounting body of the primary sealing barrier, and thecontact lips of the second seal being supported by the secondcylindrical support body in frictional contact with the cylindricalfriction body.
 11. The sealing assembly of claim 8, wherein the firstcylindrical support body of the primary sealing barrier and thecylindrical friction body of the secondary sealing barrier define alabyrinth seal between them, the labyrinth seal is arranged along theingress path (P).
 12. The sealing assembly of claim 9, wherein the firstcylindrical support body of the primary sealing barrier and thecylindrical friction body of the secondary sealing barrier define alabyrinth seal between them, the labyrinth seal is arranged along theingress path (P).
 13. The sealing assembly of claim 10, wherein thefirst cylindrical support body of the primary sealing barrier and thecylindrical friction body of the secondary sealing barrier define alabyrinth seal between them, the labyrinth seal is arranged along theingress path (P).
 14. The sealing assembly of claim 11, wherein thefirst seal of the primary sealing barrier comprises an annular profilemade of the same material as the contact lips and arranged axiallyadjacent to the annular flanged body of the second shield of thesecondary sealing barrier.
 15. The sealing assembly of claim 12, whereinthe first seal of the primary sealing barrier comprises an annularprofile made of the same material as the contact lips and arrangedaxially adjacent to the annular flanged body of the second shield of thesecondary sealing barrier.
 16. The sealing assembly of claim 13, whereinthe first seal of the primary sealing barrier comprises an annularprofile made of the same material as the contact lips and arrangedaxially adjacent to the annular flanged body of the second shield of thesecondary sealing barrier.